Well a bit later on, just before Beyonce stole the show with a long performance, Serena Williams walked out on stage at Madison Square Garden to introduce the pop star.

Williams, of course, was in the video for Beyonce’s song “Lemonade.”

With the US Open beginning this week, the move drew criticism from Canadian tennis player Genie Bouchard. The 22-year-old will begin play in the women’s draw on Tuesday. Williams is seeded No. 1 in the draw, while Bouchard is unranked.